US2377142A - Liquid bath filter - Google Patents

Description

May 29, 1945. C..J, GLANZER 2,377,142

I LIQUID BATH FILTER Filed Jan. 30, 1943 IN VEN TOR.

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Patented May 29. 1945 UNITED STATE LIQUID BATH FILTER Clarence J. Glanzer, .Northfield, Ohio, assignor to Air-Maze Corporation, Cleveland, Ohio, a corporation of Delaware Application January 30, 1943, Serial No. 474,127

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This-invention relates to improvements in liquid washed fluid filters and is particularly adapted for air filters of the oil bath type.

One of the objects of the present invention is to provide a filter for use under varying loads and where the supply of liquid for washing the filter is maintained in satisfactory amounts for all loads.

Another object of the present invention is to provide a filter adapted for use with internal crn-' bustion engines which provides efficient filtering at no load and at various engine loads up to the maximum. v

Other objects and advantages of the invention will be apparent from the accompanying draw ing and description and the essential features thereof will be summarized in the claims.

In the drawing Fig. 1 is a transverse sectional view taken centrally through a device of generally cylindrical type and having a bottom fluid outlet; Fig. 2 is a view taken partly in side elevation and partly in central transverse section of another embodiment having atop fiui'd outlet.

Prior filters of this type have been arranged for efflcient action at some special point on the load curve, but these devices were relatively inefilcient at other loads. "The present device embodies a very novel manometer type means for feeding the filter washing liquid according to variations of the fluid load passing through the filter so that eflicient washing ofthe filter occurs at all loads but carry-over of the" washing liquid is avoided.

In the form of my.device shown in Fig. l, a closed bottom annular cup II] has an upstanding ring ll spaced radially inwardly from'the outer walls of the cup In and dividing the cup into an outer reservoir l2 and an inner reservoir l3. These reservoirs are filled to the level of the full line A under normal conditions and this line 'A represents the no-load level of the liquid in the reservoirs. This point i marked on the casing by means of the annular projection Illa formed in the material of the cup. The ring I l is suitably secured in position in the cup H1, in the present instance by welding to the cup at the point I4. Spaced perforations Ha are provided in the ring rests and a manometer partition wall ISb located parallel to and radially inwardly from the ring This wall may have an inwardly turned horizontalfiange I6c at; the-bottom as shown in Fig. 1, although this is not a necessary construction, as will be apparent from Fig. 2. A flange l6d around the periphery of the member I6 rests upon the ring II to aid in the support and arrangement of the parts. Preferably (but not necessary in all cases) a number of holes We are provided through this flange for a purpose to be later described. Itwill be noted that the partition wall I6b, together with the inner cup wall I0, define an annular chamber B. Above this chamber is an annular bafiie ring I! which is held in position spaced above the chamber B by a plurality of legs 18 welded to the baffle ring and Welded in turn to the wall [6b.

Suitable'filter means I9 is provided so positioned with respect to the casing and the parts thereof that all of the fiuid passing from the inlet to the outlet of the device must pass through the filter means. This filter means may be of any suitable character but preferably, as here disclosed, comprises a cylindrical ring of screen material built according to the teachings of Patent No. 1,566,088, granted December 15, 1925 to Oscar V. Greene. This cylinder of filter material is mounted bottom and top in the annular channels 20. A top cover member 2! covers the entire top of the device and the filter means is preferably sealed top and bottom by the annular gaskets 22- of felt or other suitable sealing material.

The air inlet forthe' device is here provided by extending upwardly a ring 23 in alinement with the outer wallof the cup In and this ring is welded to the cup. Spaced radially inwardly from the member 23 is a cylindrical wall 24 which is either integral with or rigidly secured to the top cover as by welding at the point 25. This cylindrical wall extends parallel to the walls 23 and H, in the present instanc about eight of these,

equally spaced about the circumference and onequarter inch in diameter. The center line of these holes is on the line A. The inner wall of the cup I'll is provided with an upwardly extending tubular extension l5 which providesthe fluid outlet for the device. A sheet member It provides an annular shelf I ta upon which the filter means trance of material from II and radially between them. The lower edge of this wall 24 is below the normal liquid level A and also slightly below the bottom of the holes Ifnecessary or desirable, a protecting hood 2 la may be provided in connection with the cover overhanging the wall 23 so as to prevent the enabove into the fluid inlet passageway 26.

The device above described is mounted in any suitable manner. In the present instance a bracket 21 has a'tubular portion 2 8 which engages within thewalls 10b of the cup "l8 and the bottom" of 'tliecup rests uponthe bracket: as

shown in Fig. 1. The parts are held together by a spider 29 integral with the bracket 21 and receiving the threaded end 30a. of a bolt 30 which extends through the top cover and parts and there held in place by a wing nut 31. This arrangement permits the ready disassembling of the parts for cleaning or inspection.

The operation of the device above described will be explained in connection with the filtering of air for an internal combustion engine and where oil is utilized as the filter washing method. It will be understood, however, that other applications of the structure will operate in similar fashion. With the device in position on the bracket 2"! and the oil reservoirs filled to the line A, the suction of the internal combustion engine will be applied at the outlet pipe It: so that air enters the inlet 26 and flows in the direction of the arrows shown in Fig. 1. If air is drawn along this path in even the slightest degree, as for instance at no-load of the engine, this air is forced to pass through the oil in the chamber D by the fact that the wall 24 extends below the normal level of the oil in this chamber. Thus the air at no-lcad is compelled to pass through the oil and some of this oil will be entrained with the air and carried to the filter means l9, thus keeping the filter means coated with a material which increases the dust arresting capacity of the filter means, and any excess of this oil will drain by gravity down the filter means, returning either directly to the chamber B or through the holes Hie to the chamber C. In any case, this oil will then flow out the holes Ila to replenish the supply in the chamber D.

As the load increases on the engines the amount of air, and therefore its velocity through the inlet passageway and chamber D, will increase, and I utilize this increase in velocity to automatically control the further feed of oil to the incoming stream of air. As the velocity increases the oil is practically all removed by the air stream from the chamber D, the condition of this chamber being then practically empty, as indicated. by the dot-dash line (2. This oil from chamber D is carried to the screen l9, charging it with a dustretaining coating. Any excess drains back into the chamber B, raising the level toward that indicated by the dot-dash line b. At the same time the diiferential in the pressures exerted in the chambers B and C causes a change in the relative levels, as I will now explain. It will be understood by those skilled in this art that there is a greater suction on the downstream side of the filter means it than on the upstream side thereof, the difference being equal to the resistance of the passage of the stream through the filter means. This is due to the fact that chamber C is subject to the pressure at the upstream face of the filter, and chamber B is subject to the pressure at the downstream face of the filter. If, for instance, the suction on the downstream side of the filter means is equivalent to, say, a negative 3 inches of water and on the upstream side of the filter is equivalent to approximately negative '2 inches of water, then there is a 1 inch differential across the filter-means. Thus the chambers B and C constitute two legs of a -manometer means, the legs being separated by the partition wall 461). Thus, as the level rises in the leg B to the level I), the level in the chamber is depressed to the level indicated by the dot-dash line 0. The difference between the levels I) and 0 will vary with the engine load. At any load oil will trickle back through holes Ila to the incoming air stream. At the lighter loads the level 0 will be a little higher and the flow through holes Ila will be a little greater. At the heavier loads, more oil will be stored in chamber B and less will flow out of holes Ha. At heavy loads this prevents carry-over of oil to the outlet l5 by the air travelling at high velocity. The incoming stream of air i compelled to swee past the holes Ha by means of the skirt ring 24, thus inducing the air to pick up oil at this point which is entrained and carried to the filter means. Continuous washing of the screen is thus insured and the feeding of the oil is in proportion to the load on the engine because the greater the load the greater the differential between the levels b and c.

The purpose of the holes [6c is to transmit to the oil in chamber C the pressure immediately at the upstream face of the filter Hi. This, together with the fact the chamber B is subject to the pressure close to the downstream face of the filter, gives the least effective pressure differential across the manometer and holds the sealed depth of partition 18b to a minimum.

The modification of Fig. 2 is similar to Fig. l, but in this case the outlet is at the top instead of at the bottom. Parts having a similar func tion to those already described will be given similar reference characters without further description.

It will be noted that the bottom of the casing is here closed by means of the plate 32 extending between the walls Illa. There is an opening 33 through the top cover plate and the bracket 21 extends through this opening. The parts are held together by the bolt 38 which is threaded into the spider 2! of the supporting bracket and which is clamped against the bottom of the casing by means of the clamping. plate 34 and the wing nut 3|. Oil leakage atthe bottom is prevented by means of the gasket 36. The normal oil level A is indicated as before by the projecting annular rib Illa.

The operation of the modification of Fig. 2 is similar to that already described in connection with Fig. 1. The air enters at the inlet 26 and travels as indicated by the arrows between the plates 23 and 24 downwardly to a point where the plate or ring 24 compels the air to pass beneath the oil or other fluid in the reservoir in the chamber D. The air then travels upwardly past the holes I la, then through the filter means l9, and upwardly through the outlet. The differential which causes the flow of fluid through the filter means is transmitted to legs B and C of the manometer means as before, causing the level in the leg B to rise to the dot-dash line b and depressing the level in the leg C to thedotdash line 0. Whenever the engine is workin at any appreciable load the chamber D is practically emptied as indicated by the dot-dash line d. The oil from this chamber is carried up into the filter means [9, charging the fitler means for more efficiently arresting dust and the excess draining down to the inner manometer leg B. The hydraulic head represented by the differences in height between the levels 17 and 0 causes oil to continuously pass out of the openings Ila into the incoming fluid stream so that there is a continuous replenishment of the oil in the filter means l9, keeping the filter means charged with liquid and washing the collected dirt down into the bottom of the casing means In the modification of Fig. 2, as'in Fig. 1,the air must pass through the oil inthe-reservoir D at no-load or very light engine loads, and at other engine loads up to the maximum oil is continuously entrained in the incoming air stream as it passes the openings I la and thefiow of oil through these openings is controlled by the manometer means 3-0 which stores more oil in chamber B as the load on the engine increases.

In all of this description nothing has been said about the cross sectional shape of my device, but the embodiments here shown are intended to show walls generally circular or cylindrical and the sectional views shown are intended to be taken diametrically across the circular sections. Y

While the flow of the air or other filtered fluid has here been shown as beginning at the radially outermost point of the device and travelling radially inwardly, those familiar with this art will understand that this is for convenience and is not essential for the carrying out of the principles here disclosed.

It will be noted that the ring ll completely separates chambers C and D because of the tight 7 joint at I4. Thus the only 011 reservoir that can be blown empty by the incoming air stream is the chamber D. This is a definite amount so chosen as to properly charge the filter and store a little in chamber B. The level in chamber C can never fall below holes I la and the depth from here to the bottom of partition 16b is greater than the diiferential across the filter at heavy engine loads so that the manometer can never be by-passed under wall l6b even by sudden surges in suction at the outlet l such as occur often in internal combustion engines.

What I claim is:

1. In a liquid bath filter, cup-shape casing means open at the top and having a generally cylindrical side wall and closedat the bottom to provide a well, a generally cylindrical partition wall extending upwardly from the bottom of said ing said larger reservoir into a differential pressure manometer means, there being openings or limited size through said partition wall spaced above the bottom of said casing means, and there being an air outlet leading from said casing means radially inside said filter element.

2. In a liquid bath filter, cup-shape casing means open at the top and closed at the bottom to provide a well, a top cover for said casing means, there being an air inlet opening in said casing means near the top, means providing an air-directing passageway extending downwardly from said inlet to a point near said bottom and then inwardly and upwardly therefrom, partition wall means extending upwardly from said bottom dividing said well into a larger reservoir radially inwardly from said passageway and a smaller reservoir radially outside said partition wall in said passageway, a generally cylindrical filter element having its outer face radially inwardly from said passageway and extending from a point above said partition wall to said cover and sealed thereagainst, said air-directing passageway and said partition wall and said element being substantially concentric, an imperforate division wall extending downwardly from the bottom of said element to a point adjacent the bottom of said larger reservoir, there being casing means and spaced radially inwardly from the cylindrical wall of said casing means and dividing said well into two reservoirs, one smaller radially outside said partition wall and one larger radially inside said partition wall, a top cover above and spaced from said casing means providing an air inlet above the cylindrical wall thereof, an imperforate generally cylindrical skirt extending downwardly from said cover and concentric with and positioned radially between said casing means cylindrical wall and said partition wall and providing a downwardly extend- ,ing passageway outside said skirt and providing an upwardly extending passageway inside said skirt, a generally cylindrical filter element radially inwardly from said skirt and extending upwardly from a point above said larger reservoir substantially to said cover and there sealed against by-passing of air around said element, an imperforate division wall extending from the bottom of said filter element downwardly to a Joint adiacent the. bottom or said well and dividopenings of limited size through said partition wall spaced above the bottom of said casing means, and there being an air outlet leading from said casing means radially inside said filter element.

3. In a filter of the liquid-washed type, a filter element in the form of a generally cylindrical wall having a length at least several times the wall thickness and positioned with the cylindrical axis vertical, casing means including an inlet and an outlet for directing gaseous flow through said element generally radially of said cylindrical wall, said cylindrical wall being open and free for gaseous flow therethrough along its entire length, means coacting with said casing beneath said wall, the upper portion of said legs being in pressure communication one leg with the upstream side only and the other leg with the downstream'side only of said element, and means for limited liquid flow from said well to said reservoir positioned in that leg communicating with the upstream side of said element and substantially at the level where liquid in said two legs is at a common level when no gaseous stream is flowing.

CLARENCE J. GLANZER.

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